Ceramic stenciling ink and vehicle therefor



Patented May. 4, 1943 CERAMIC STENCILING ANDYEHICLE THEREEUR Frederick Shurley, Windsor, Ontario, Canada,

assignor to Guthrie Ceramic Labelling & Machinery Co. Inc., Dover, DeL, acorporation of Delaware No Drawing. Application June 30, 1939, Serial'No. 282,073

Claims. (Cl. 106-30) This invention relates to ceramic stenciling inks and vehicles therefor, and it comprises an air-drying carrier or vehicle for vitriflable' inks or colors of the type which are usually used for decorating and coating articles made of china, porcelain, glass and other ceramic materials, said vehicle comprising the combination of a liquid oleo-resin, such as Venice turpentine, at least one resin of the nature of copaiba resin, molasses and a small'amount of a phthalate ester; said vehicle being adapted to be used in admixture with the usual vitriflable pulverized enamel frit, pigments, etc., to form the stenciling'ink or color of the present invention, which is adapted to be applied in the conventional manner by spraying, brushing or screening through a stencil of meshed material such as silk, chiffon, organdie, cotton or fine wire mesh; all as more. fully Hereinafter set forth and as claimed.

The production of multicolored vitreous enamel designs on ceramic articles, metals, etc., is usually accomplished in the art by the use of vitriflable colors or enamels, consisting of finely divided quartz or quartz like materials, commonly called enamel frits, which have been finely pulverized, mixed with metal oxides for coloring purposes and then suspended in a vehicle. In one of the methods used in the art, the ink has been applied by the use of a mesh stencil, the ink being forced by means of a squeegee through the meshes of a screen of silk, for example, part of the screen being blocked out in order to form the desired design. It has been recommended to employ an oily vehicle in the ink used in this operation, containing a paraflin or vegetable oil, for example, and the ink has usually been of pasty consistency.

I have found that more satisfactory stenciling inks and colors can be produced by the use of what may be called a non-oily air-drying, resinous vehicle in which resins, oleoresins and gums are combined, in such manner as to produce a semi-liquid consistency so that the ink can be readily pressed or squeegeed through the fine meshes of a fabric or a metal stencil. Several important advantages are gained by the use of this novel vehicle or medium.

A coloring composition or paint having an oil vehicle must be heated in order to dry the paint before the articles can be stored prior to firing. Such compositions are not air drying. This is an important disadvantage. Further I have found that oil vehicles leave an undesirable carv bonaceous residue on the article after firing which causes discoloration and which also prethe whole.

vents the free flowing of the coloring matter during firing. If several coats are to be applied to an article it is necessary to heat the article between the application of each coat in order to volatilize the vehicle and to produce a dry surface for the application'of the following coat. And in addition it has been found that the use of an oily vehicle tends to produce an undesirable reducing atmosphere in the furnace or lehr in which the coatings are vitrified. All of these disadvantages in the use of an oily vehicle have been overcome by the use of the resinous vehicle of the present invention.

The vehicle of the present invention is compounded of certain resins and oleoresins instead of oils. My preferred vehicle consists of copaiba resin, turpentine, molasses, dammar and dibutyl phthalate in proportions producing a relatively thin vehicle. It is, of course, to be understood that other resins and oleoresins having characteristics similar to those of copaiba resin, dammar. and turpentine may be used as substitutes. Likewise other liquid alkyl phthalates having properties similar to dibutyl phthalate may be used in place thereof.

Although the proportions of the constituents of my vehicle may be varied within certain limits I have found that best results are obtained when the copaiba resin or equivalent constitutes about 57 per cent by weight of the composition while the turpentine constitutes about 28 per cent of The molasses and dammar should each constitute about 7 per cent and the dibutyl phthalate about 0.05 per cent of the composition.

Other similar vehicles within my invention may contain from about 55 to 60 per cent of copaiba resin, 32 to 37 per cent of an oleoresin obtained from coniferous trees, about 7 per cent of molasses and from about 0.04 to 0.06 per cent of a liquid dialkyl phthalate.

It has been found that the following mixture gives very good results:

Parts Copaiba resin 32 Venice turpentine 16 Molasses 4 Dammar (crystal dammar varnish) 4, Dibutyl phthalate The molasses may be of the type known in commerce as black strap.

The vehicle is prepared by mixing together and stirring slowly the copaiba resin, Venice turpentine and dibutyl phthalate. To this mixture is added the molasses and dammar. After preparing the vehicle in this manner the powdered solids are added and thoroughly mixed in to produce the finished ink or color.

The color should be milled finely enough .so that, when a small portion is diluted with turpentine on a piece of glass and the excess is shaken oil, it will show a smooth color free from all lumps and grains when observed through a magnifying glass. Otherwise the color is likely to contain particles which will clog the screen or produce pinholes therein. Grinding of the color to pass through a 200 mesh screen is desirable.

In order to produce uniform results the milling or grinding of the color and the printing should be done in a warm room with little temperature variations from day to day. using the same proportions of vehicle and oxides or pigments. Any substantial variation in the temperature will cause variations in the ink and may cause diiflculties in the printing. Inthe operation of pressing the ink through a screen by means of a squeegee, the latter must be wiped perfectly clean and free from dust in order to prevent clogging of the screen. In general it may be said that the thinner or more liquid the medium the better, owing to the fact that it will then leave less carbon residue. After the application of the ink to an article to be colored. it can be left to air dry, after which it is fired to burn in the color in the conventional manner.

The stenciling ink. after being applied to an article will, in a short time, dry sufllciently at room temperature to permit storage of the articles. Furthermore it has been found that the colors do not deteriorate after long storage periods at room temperature even though the articles have not been fired.

It isnot essential that a first coating be fired before applying a second coat thereto, since each coat dries hard in a short time at room tempera tures. One can therefore, completely finish a multicolored designwithout having-to fire each coating separately.

While I have described what I consider to be the best embodiments of the present invention, it is evident that various modifications can be made both in the ingredients and in the proportions of the ingredients used in my vehicle. Thus, while dibutyl phthalate has been mentioned as one of the minor ingredients of my vehicle, this can be replaced by any of the other liquid alkyl phthalates, such as methyl phthalate, for example. The Venice turpentine can be replaced by any of the liquid oleoresins which are obtained from coniferous trees. And while my preferred composition contains both copaiba resin and dammar, it is only necessary that at least one gum or resin of this nature be present provided that it is combined with the other ingredients in such proportions as to produce a liquid vehicle. While I have described my vehicle particularly in connection with its use in making inks for the silk screen process, it has many obvious advantages when used with other processes of ceramic printing. It may be employed, for example, in the use of cut stencils with ties and in applicatime where the ink is applied by sprayin lithographing or printing or by any other means known to the art. Other modifications which fall within the scope of the following claims will be immediately evident to those skilled in this art.

what I claim is:

1. A non-oily, resinous air-drying vehicle for vltrifiable stenciling inks used for ceramic printing, comprising a mixture consisting principally of copaiba resin and Venice turpentine and smaller amounts of molasses. dammar and dibutyl phthaiate in proportions producing a thin liquid vehicle.

2. A non-0 W. resinous, air-drying vehicle for ceramic stenciling inks consisting of 82 parts copaiba resin.'16 parts Venice turpentine, 4 parts molasses, 4 parts dammar and a; part dlbutyl phthalate.

3. A non-oily, resinous, air-drying vehicle for ceramic stenciling inks consisting of about 57 per cent copaiba resin, about 28 per cent turpentine, about 7 per cent molasses, about 7 per cent dammar and about 0.05 per cent dibutyl phthalate.

4. A non-oily, resinous, air-drying vehicle for ceramic stenciling inks comprising a mixture containing about 57 per cent copaiba resin, about 35 per cent of a liquid oleoresln obtained from coniferous trees, about 7 per cent molasses, and about 0.05 per cent of a liquid di-alkyl phthalate.

5. A non-oily, resinous, air-drying vehicle for ceramic stenciling inks comprising a mixture containing from 55 to 60 per cent copaiba resin, 32 to 37 per cent of an oleoresin obtained from coniferous trees, about 7 per cent molasses and 0.04 to 0.06 per cent of a liquid di-alkyl phthalate.

6. A ceramic stenciling ink comprising a pul- .verized, vitrifiable enamel frit and solid coloring matter dispersed in a non-oily, air-drying, resinous vehicle consisting substantially of 55 to 60 per cent of copaiba resin, 32 to 3'7 per cent of a liquid oleoresin, about 7 per cent of molasses and from 0.04 to 0.06 per cent of dibutyl phthalate.

7. A non-oily, resinous air-drying vehicle for ceramic stenciling inks, comprising an oleoresin liquid composed of 57% copaiba resin, 28% turpentine, .05% dibutyl phthalate and 7% dammar varnish to form a relatively thin vehicle, whereby when mixed with an oxide or frit, forms an intimate mixture that adheres to a glass or metal surface and dries without the application of heat, thereby enabling other colors to be superimposed to form a. multi-color design which can be fired or fused at one operation.

8. A non-oily, resinous, air-drying vehicle for vitriiiable stenciling inks used for ceramic printing, which consists of a mixture containing a liquid oleoresin, copaiba resin, molasses and a small amount of a liquid dialkyl phthalate ester in proportions producing a thin liquid vehicle in the general proportions of more than one-half being copaiba. resin, one-half thereof being liquid oleoresin, about a fifth of the latter being molasses, and less than 1% being dialkyl phthalate, said vehicle when mixed with ceramic coloring material, forming a stenciling ink capable of adhering to a glass or metal surface and drying without the application of heat, thereby enabling colors to be superimposed to form a multi-eollored design which can be fired in one operation. 9. A non-oily, resinous, air-drying vehicle for vitrifiable stenciling inks used for ceramic print- -ing, which consists of a mixture containing a liquid oleoresin, copaiba resin, dammar, molasses and dibutyl phthalate in proportions producing a thin liquid vehicle in the general proportions of more than one-half being copaiba resin, onehalf thereof being liquid oleoresin, about a fifth of the latter being molasses, and less than 1% being dibutyl phthalate. said vehicle when mixed with ceramic coloring material, forming a stenciling ink capable of adhering to a glass or metal surface and drying without the application of being liquid oleoresin, about a fifth oi the latter being molasses, and less than 1% being dibutyl phthalate, said stenciling ink being adapted to be applied to ceramics by spraying, brushing or screening through a stencil of meshed material followed by firing, said vehicle being capable of drying without the application of heat, thereby enabling colors to be superimposed toform a multi-colored design which can be fired in one 10 operation.

FREDERICK SI-IURLEY. 

